The invention provides a method and a device for looped network protection. The method is applied in an secondary node of a looped network; the main node and the secondary node of the looped network both comprise looped ports connected with a central network; the method comprises the following steps: the secondary node receives a detection message transmitted by a main port and an secondary port of the main node; when the secondary node does not receive the detection message transmitted by the main bode within preset time, the looped port of the secondary node connected to the central network is changed from a blocked state to an opened state; the address fresh operation of the secondary node is carried out, and an address fresh message is transmitted to the direction of the main port so as to instruct a transmission node which receives the address refresh message to carry out address refresh, thereby changing the transferring direct of the transmission node to a service message. With the adoption of the method and the device, the problem that the service flow may be interrupted because of faults at a looped network is avoided effectively.